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Install & Self-host Voltaire

This guide is intended for developers wishing to spin a instance of Voltaire ERC-4337 Python bundler for handling User Operations. Voltaire is open source and can be found on


Looking for a quick bundler instance? Use one of our public hosted endpoints for your developement


The quickest way to get started is to use the docker image.

  • Install docker
  • Find the latest Voltaire releases
  • Run the following command to start a geth node and deploy the EntryPoint contract:
docker run --net=host --rm -d$VOLTAIRE_VERSION --entrypoint $ENTRYPOINT --bundler_secret $BUNDLER_SECRET --rpc_url $RPC_URL --ethereum_node_url $ETHEREUM_NODE_URL --chain_id $CHAIN_ID --verbose

This command will pull the latest docker image and will then start the bundler to listen for UserOperations. Once running, you can then send User Operation to the following if you used the default $RPC_URL:

--entrypointAddress of the entrypoint contract
--bundler_secretPrivate key of the bundler. Use any EOA's to be the secret and make sure it's funded with some ETH
--keystore_file_pathBundler Keystore file path. Defaults to first file in keystore folder (optional)
--keystore_file_passwordBundler Keystore file password. Defaults to no password (optional)
--rpc_urlURL of the rpc endpoint you will be hosting. Use as default
--rpc_portRPC serve port number. Defaults to 3000 (optional)
--ethereum_node_urlPass the node url of your own instance if you are running a full node locally, or a link to a full node endpoint from an RPC provider - defaults to
--chain_idChain ID of the network the bundler will operate in
--verboseTo get verbose logs (optional)
--debugExpose _debug rpc namespace for testing (optional)
--unsafeIn order to implement the full spec storage access rules and opcode banning, it must run against a go-ethereum or erigon node, which supports debug_traceCall with javascript "tracer". Specifically, hardhat node, ganache, infura and alchemy nodes do NOT support this API. You can still run the bundler with such nodes, but with --unsafe so it would skip these security checks (optional)
--legacy_modefor netwroks that doesn't support EIP-1559 (optional)
--bundle_intervalSet the bundle interval in seconds for the auto bundle mode - set to zero for manual mode (optional)
--whitelist_entity_storage_accesslist of entities to whitelist for storage access rules (optional)
--metricsenable metrics collection using prometheus and grafana (optional)
--versionshow program's version number and exit (optional)

To know about all flags:

docker run --rm -it$VERSION -h

RPC Provider

If you want to run voltaire locally and have a paid plan with an RPC provider for a full node that supports debug_traceCall with javascript "tracer", you can simple replace $ETHEREUM_NODE_URL with the link to the rpc endpoint. If it doesn't support a javascript tracer, you can run with the --unsafe flag for testing purposes. This mode is not meant to be used in production.

Local Full Node

If you are running your own full node, simply pass your own node url in --ethereum_node_url. If you want to run your own node, which comes with superpowers, follow the instruction below to run GETH using docker. You can also run a different client implentation.

Voltaire works well with go-ethereum and erigon. Contact us if you would like to see Voltaire tested with a different client.


Ubuntu Instructions

Install Poetry

curl -sSL | python3 -

Install dependencies

poetry install

Make sure you are using the right python version

poetry env use python3.11

Install Docker

Follow the installation guide to install docker on ubunutu

Post docker installation

Follow the instruction for docker's post linux instalation

Start GETH

docker run --rm -ti --name geth -p 8545:8545 ethereum/client-go:v1.10.26 \
--miner.gaslimit 12000000 \
--http --http.api personal,eth,net,web3,debug \
--http.vhosts '*,localhost,host.docker.internal' --http.addr "" \
--ignore-legacy-receipts --allow-insecure-unlock --rpc.allow-unprotected-txs \
--dev \
--verbosity 4 \
--nodiscover --maxpeers 0 --mine --miner.threads 1 \
--networkid 1337

In another terminal, deploy the EntryPoint and fund the signer

geth --exec 'loadScript("test/deploy.js")' attach

Set the ENTRYPOINT environment variable

source test/init-params 

Run the bundler

In a new terminal

poetry run python3 --entrypoint $ENTRYPOINT --bundler_secret $BUNDLER_SECRET --chain_id $CHAIN_ID --verbos

Test the bundler by cloning eth-infinitism/bundler-spec-tests

Follow the instruction in eth-infinitism/bundler-spec-tests to install dependencies and run the test